We previously reported a continual decline in anti-HCV prevalence among young injectors from Glasgow and Lothian between 1990 and 1997. The original study was extended to ascertain if the anti-HCV prevalence among injectors from Glasgow, Lothian, Tayside and Grampian had changed since 1997. Residual sera from injectors who had undergone attributable anti-HIV testing were tested anonymously for anti-HCV. In all four regions, no significant changes in prevalence were found among those aged < 25 years during the late 1990s (Glasgow 1997-9/00: 43%-41%; Lothian 1997-9: 13%-17%; Tayside 1997-9: 45%-35%; Grampian 1996-9: 28%-29%). Among those aged > or = 25 years, significant decreases in prevalence were only observed in Glasgow (1997-9/00: 79%-72%, P = 0.03) and Lothian (1997-9: 54%-45%, P = 0.05). The findings highlight that existing harm reduction measures, acknowledged as having helped to reduce the spread of HCV, are not sufficient to bring this epidemic under control and reduce transmission to sporadic levels.